Parasitic Leiomyoma After Laparoscopic Total Hysterectomy and Bilateral Salpingo-Oophorectomy, a Mimicker of Pelvic Neoplasm

Abstract

Abstract Parasitic leiomyomas are rare occurrences that may mimic malignancy and thus present a diagnostic dilemma. They are thought to arise from a pedunculated subserosal leiomyoma that undergoes torsion and detaches from the uterus, surviving by revascularization from adjacent structures, or from iatrogenic implantation during surgery, more common with the clinical popularity of laparoscopic surgery and power morcellation. We report a case of parasitic leiomyoma with degenerative changes in a 57-year-old female who was initially found to have a 6.5-cm left adnexal mass and multiple submucosal and intramural masses consistent with leiomyoma by abdominal pelvic computerized tomography test (CT) 7 years prior to presentation. She experienced severe abdominal discomfort that persisted after total abdominal hysterectomy and a 7.8-cm mass was found in the left pelvic cavity on reevaluation. Grossly, the pelvic mass was a 6.5-cm tan-gray ovoid firm mass with a 4.0-cm cystic cavity. The cut surfaces of the solid areas/cyst wall were gray-white and firm with focal yellow streaks. Microscopically, there was central cystic degeneration, with cyst wall showing extensive granulation tissue. The solid portion also showed extensive hyaline degeneration, fibrosis, and perinodular hydropic degeneration. Smooth muscle differentiation was evident at the periphery of the mass, confirmed by strong staining with desmin and smooth muscle actin. This represents a parasitic leiomyoma left behind following the first procedure and it developed degenerative changes. In addition to the high index of suspicion for malignancy in assessing adnexal masses, degenerating parasitic leiomyomas should be included in the differential diagnosis of such mass lesions.